Option 1 : Rs. 93750

**Given:**

The selling price of the plot is directly proportional to the square of the area of plot in m^{2},

The cost price of the square-shaped plot is Rs. 50000

And the profit percent of a dealer is 25% on selling square-shaped plot

The dealer gains 50% on selling the rectangular plot

The length and breadth of the rectangular plot is 30m and 20m while the side length of the square plot is 20m

**Formula used:**

S.P = C.P × (100 + profit %) /100

C.P = S.P × 100/ (100 + profit %)

S.P = C.P × (100 - loss %) /100

**Calculation:**

According to question,

Selling price ∝ (area of plot)^{2}

Area of square plot = (20)^{2 }= 400 m^{2}

Area of rectangular plot = 30 × 20 = 600 m^{2}

Selling price of square plot = 50000 (125/100) = Rs. 62500

Now according to question

⇒ 62500/ S.P of rectangular plot = (400/600)^{2}

⇒ S.P of rectangular plot = Rs. 140625

So, the C.P of rectangular plot = 140625 × 100/150

Hence, C.P of rectangular plot = Rs.93750